In 2005 Will Reiser, then just 25, learned that he had cancer. After undergoing a successful surgery, Reiser's friends, including Seth Rogen, encouraged him to write a script about his experiences fighting cancer. Six years later, the result is "50/50," starring Joseph Gordon-Levitt.

JGL stars as Adam, a young man who, along with his best friend, Kyle (Rogen basically playing himself), works at Seattle's NPR station. He's a cautious young man passionate about his work, with few if any vices, and a girlfriend, Rachael (Bryce Dallas Howard), who paints abstracts of dubious quality. Weeks of back pain lead to an MRI, which leads to a diagnosis of a malignant tumor growing along Adam's spine.

Films about cancer tend to be fairly maudlin affairs that aspire for you to have a good cry and just let it all out. But that's not Reiser, who in his career has worked with comedians as irreverent as Rogen and Sacha Baron Cohen. What's so funny about cancer? Using your diagnosis to pick up women, wolfing down pot brownies with fellow patients, an afternoon in the backyard playing with knives fire and hatchets… Though you won’t walk out of "50/50" thinking cancer looks like fun—in fact, it looks miserable.

But director Jonathan Levine never tries to make you feel anything forced or contrived. There are no sweeping violins or emotionally manipulative moments. Levine established himself as someone to watch in 2008 with his sophomore effort, "The Wackness," a coming of age film about a NYC pot dealer. The promise of "The Wackness" comes to fruition in "50/50."

Wielding perhaps the best sidelong glance in Hollywood, occasionally topped off with a furrowed brow, Gordon-Levitt proves again that he's among his generation's most talented actors, conveying the pathos and pain as well as the laughs in Reiser's script, his innate sincerity pulling you in.

It would be easy to dismiss Rogen's performance as simply Rogen playing Rogen, but the fact is, he basically is playing Rogen, and the reality is that he's one funny man—who knew there any new jokes to make about fellatio?

The great Rosie Greer once assured a generation that it's alright to cry, "50/50" is here to assure you it's alright to laugh--at cancer.